Telephone system.



A. H. DYSON.

TELEPHONE SYSTEM.

APPLICATION FILED APR. 21, I906- Patented 3O, 7 SHEETS-SHEET I.

IFIIIIIIHIII" A'rToraNnY.

A. H. DYSON. TELEPHONE SYST' EM.

APPLICATION FILED APR. 27, 1906; v 1,184,934. Patented May 30, 1916.

7 SHEETS-SHEET 2- L/Mz INVENTOR ATTORNEY A. H. DYSON.

TELEPHONE'SYSTEM.

I APPLICATION FILED APR. 27,1906. 1,184,934. Patented May 30,1916.

7 SHEETSSHEET 3- NVENT'OR ATTORNEY.

WITNESSES 1- A. H; DYS ON. TELEPHONE SYSTEM.

APPLICATION FILED APR. 27, 1906.

T SHEETS-SHEET 5- wl-ruase ss M n ATTORHEY.

Patented May 30,1916.

A.H.DYSON.

TELEPHfiNE SYSTEM. APPLICATION man APR. 21,1906.

Patented May 30, 1916.

1 SHEETS-SHEET 6.

'A.H.DYSON TELEPHONE SYSTEM.

AP PLICATION FILED APR. 27, I906.

Patented May 30,1916.

7 SHEETS-SHEET I- I hvnissssz E \NVENTQR ATTORNEY UNITED. STATES PATENTornioa.

ALFRED H. DY SOIN', OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNEASSIGNMENTS, TO KELLOGG SWITCHBOARD &, SUPPLY COMPANY, A CORPORATION OFILLINOIS.

TELEPHONE SYSTEM.

Be it known that I, ALFRED H. DYSON, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a new and useful Improvement in Telephone Systems, of whichthefollowing is a specification.

The present invention relates to telephone exchange systems and has forits general object to provide a combined manual and automatic system inwhich a calling party,

' provided with automatic substationequipment, may automaticallyestablish talking connection with a substation provided with eitherautomatic or manual equipment; and

in which a subscriber, provided with the usual manual substationequipment, may,

through the agency of the usual central station operator, obtainconnection with either it manually or an automatically equipped ine.

Another object of the invention is to so construct and arrange theautomatic portion of the equipment that it may be readily and cheaplyadded to existing manual systems for cooperation therewith whenextensions to such systems are required.

Other objects are to provide a system which shall employ a minimum ofrelays and other parts and be eflicient in operation and economical toconstruct,.install and maintain.

, i In carrying out my invention, each telephone line entering theexchange, whether manually or automatically equipped, is pro= vided withterminals in the form of multiple jacks for manual connection andmultiple switch contacts for automatic connection, and

each automatically equipped line is further connected with movableswitch contacts. The movable switch contacts of a calling line cooperatewith interconnecting link-circuit apparatus and switching mechanism toestablish connection from the calling line to the fixed contacts of acalled line, whether manually or automatically equipped, in re sponse tothe manipulations of a calling device at the calling line substation.The fixed multiple switch contacts for each line are arranged inv pairs,and the link-circuit which establishes the final connection with acalled Serial N 0. 314,018.

devised a novel arrangement of switch apparatus and circuits by whichabusy signal may be transmitted to the calling party or not, inaccordance withthe electrical conditlon of the pair of called linecontacts thus engaged.

The invention also includes means for mu tomatically ringing 'a calledparty when his line is found to be idle and means for inter rupting thenormal connection between an automatically equipped line and its movableswitch contacts as soon as connection is established with its fixedcontacts. This results in novel circuit arrangements for those switchescommonly called individual and connector switches.

-It willbe of course understood that in developing the invention alongthe lines indicated, I have provided features and circuit arrangementswhich are capable of use in various other relations. Some of these areapplicable to manual and so-called semiautomatic systems, as well as tofull automatic systems.

The invention contemplates other features and arrangements which,together with the above, will be more fully understood upon reference tothe following detailed description, taken in connection with theaccompanying drawing, which illustrates one embodiment of my invention.

Referring to said drawing, Figure 1, which includes sheets '1, 2 and 3,is a diagram of a portion of a system constructed in accordance with myinvention; Fig. 2 is a side elevation of a private or individual switchwith which each automatically equipped line is provided at the exchangeFig. 3 is an elcvation of the movable contacts or wipers and the fixedor bank contacts of said switch; Fig. 4 is a view partly in section,illustrating the arrangement of said wipers on their supporting shaft;Fig. 5 is a partial sectional view of a connector switch, illustratingin plan the primary magnet, together with its associated mechanism, thesection being taken on a plane indicated by line 5-5 of Fig. 9; Fig. 6is a side elevation of the connector, illustrating particularly thesecondary magnet and its associated mechanism, togetherwith thearrangement of the wipers and bank contacts; Fig. 7 is a detail of theoff-normal switch associated with said connector; Fig. 8 is a sectionalview of the con- Patented May so, 1916.

vation of said connector, viewed at right angles to that of Fig. 6; Fig.10 is an elevation viewed from the right of Fig. 9 and illustrating theprivate and release magnets of the connector and their associatedmechanism; Figs. 11- and 12 are detail views ,illustrating the actuatingmagnets of control switch mechanism included between the private switchmechanism and the first selector; Fig. 13 illustrates the release magnetof a selector switch, together with its associated switching mechanism;and Fig. 14 is a side elevation of such a selector.

' movable contacts 14-15 of an individual switch C. Manual connectionbetween a manually equipped calling line and any other line, whetherautomatically or manually equipped, is obtained by means of the manuallyoperated link-circuit apparatus H. Automatic connection is obtainedbetween an automatically equipped calling line and any other linethrough the agency of electrically operated switch and link-circuitmechanism including the individual switch C of the calling line, thecontrol switch mechanism D, the first selector switch E, second selectorswitch F and the connector switch G. In practice, it is found that on abasis of ten thousand lines these switches may be apportioned asfollows: ten thousand individual switches C, one thousand control switchmechanisms D and selector switches E, one thousand second selectorswitches F and one thousand connector switches G. \Vith thisapportionment, each line will be multipled to ten connectors, eachconnector to one hundred second selectors, each second selector to athousand first, selectors, and each first selector to ten.

private switches. It is, of course, to be understood that where anultimate capacity of only one thousand lines is desired, one set ofselector switches may be omitted, and it should also be understood thatthe above figures form a basis upon which extensions to existing manualsystems of automatic equipment may be made, and that the automaticequipment may be added from time to time, according to the requirementsof the service.

' \Vith the above preliminary outline 015 the system, it is thought itwill be best understood by. entering at once into a statement of itsoperation.

The manual portion of the system illustrated is old and well known inthe art and, therefore, the operation of establishing connection betweenmanually equlpped calling and called lines need be described butbriefly. Assuming that a party at substation B at the left in Sheet 3 ofFig. 1 desires to converse with a party at station B at the right insaid figure, he removes his receiver 16 from its hook 17 and therebycompletes a circuit from ground at the exchange, over the line limb 18,

through the switch-hook 17, receiver 16,

transmitter 19, line limb 20, winding of the line relay 21, battery 22to ground, thereby completing a circuit to ground through the line lamp23 and causing it to light, as a signal to the operator that connectionis desired. Upon observing this signal, the operator will insert theanswering plug 2 1 into the answering jack 10 associated with thecalling line and depress her listeningkey 25 to learn the Wishes of thecalling party. The insertion of the plug 24; into the ack will completea circuit from the live pole of the battery 26, through the sleeve relay27 of the link-circuit apparatus H, through the plug and jack contactsand the winding of the cut-off relay 29 to ground, thereby energizingsaid cut-off relay to remove the control of the line relay 21 and itsassociated signal 23 from the control of the calling party and tocontinue the line limbs 18 and 20 to the jack contacts. As soon as thecut-off relay 29 is energized, a circuit will be completed in shuntthereto by Way of the line limbs 1820, plug and jack contacts and thewinding of the tip relay 30 to ground. Over this latter branch,sufiicient current will flow to energize the relay 30 and therebyinterrupt the circuit of the supervisory lamp 31 and prevent itsdisplay. With the parts in this condition, the breaking of the circuitat the substation, by the return of the receiver to its hook, wouldinterrupt the flow of current through the tip relay 30 and allow itscontact to return to normal, while enough current would flow through.the sleeve relay 27 to maintain it actuated and thereby maintain thecircuit of-the supervisory lamp 31 complete. The operator, having madethis connection, now depresses her listening-key 25 and thereby includesher telephone set in circuit with the calling station and, afterlearning the desires of the calling party, tests the called line todetermine its busy or idle condition by touching the tip of her callingplug 32 against the test contact of the ack 10 of the called line.

If the line is busy by reason of connection with a manually operatedlink-circuit, it I will be seen from the circuit traced through thecut-off relay 29 of the calling line that there will be a potentialabove that of ground upon the test contact of the jack automaticallyconnected, a like potential will be found on the test contact of thejack supplied over connections hereinafter indi cated. If the, desiredline is found to be idle, the operator will insert the calling plug 32into the jack 10 of said line and thereby actuate the cut-off relay 29of that line to establish connection between the line limbs and the jackcontacts and to destroy the substation control of the line relayandsignal. Upon establishing this connection, the operator will depress theringing key 36 and thereby apply ringing current to actuate thecall-bell of the desired party and, at the same time, supply batterycurrent to the cut-off relay 29 over the sleeve side of the circuit. Assoon as the ringing key is restored to normal, the supervisory lamp 37will be lightedand will remain in this condition until the called partyanswers. This occurs by reason of the energization of the relay 34 overa circuit through the cut-off relay of the called line, similar to thattraced in connection with the calling line. However, as soon as the callis answered, a

path will be completed through the winding of the tip supervisory relay38 and sulficient current will be supplied to actuate said relay tobreak the circuit ofthe supervisory lamp 37 and cause itsextinguishment. With the parties thus connected, both supervisory lamps31 and 37 remain dark; and at the end of conversation, the lighting ofboth lamps is a signal to the operator to, disconnect, resulting fromthe restoration of the subscribers receivers.

Referring now to the operation of the automatic portion of the system;assuming that a party at substation A at the left of Fig. 1 desires toconverse with a party at substation A at the right of said figure, andassuming that the number of the latters telephone is 3456, the party atthe former station first takes down his receiver and, by that act, setsthe individual ,switch C, associaied with his line, into operation toautomatically select an idle link-circuit and its associated firstselector switch. The removal of the receiver 39 from its switchhook 40com letes a bridge between the two line limbs -S, through thetransmitter 41 and the normally closed contacts 42 of the calling deyiceT.

At this time, the

wipers 14 and 15 of the private switch are in engagement respectivelywith the ground contact 43 and the contact 44 which is per-, manentlyincluded in circuit with the winding of the primary magnet PM of saidswitch and the battery 45. Since the line limbs P and, S are normallycontinued through thecontacts of the cut-off relay CO to the wipers14-15, as soon as the calling party removes hisreceiver, circuit iscompleted from the live pole of the battery 45, through the Winding ofthe primary magnet PM, contacts 4415, contacts 46-47, line limb S,through the substation, line limb P, cut-01f relay contacts 48-49, wiper14 and contact 43 to the grounded side of the battery. The closing ofthis circuit will energize the relay PM to attract its armature contacts50-51 into engagement with the contacts 52-53 respectively. The closingof the contacts 50-52 will complete a circuit from the live pole ofthebattery through the winding of the secondary magnet SM, whichautomatically interrupts its energizing circuit at the contacts 5455,and, through the agency of the mechanism associated therewith anddisclosed in Fig. 2, steps the wipers 14, 15 and 56 of the switch overthe associated bank contacts. The bank contacts 43 and 44 are ofsufficient length to remain in engagement with the ,wipers 14 and 15respectively after they have been moved one step, while the groundedcontact '57, which cofiiperates with the wiper 56, is

not engaged thereby until the switch has taken one step. Upon vthe firststep of the private switch C, the spring contact 58. of the off-normalswitch 0 moves from engagement With the spring contact 59 intoengagement. with the spring contact 60,

while the spring contacts 61 and 62, which are normally in engagement,are disengaged and moved into engagement respectively 'With the contacts63 and 64. Thereupon a circuit is completed from the live pole of thebattery, through the contacts'50 and 52 of the primary magnet PM, switchcontacts 58,"64-'62and the winding of the cutoff relay CO to ground. Atthe same time,

connection is established from the live poleof the battery, through theresistance 65,

contacts 63-61 to the bank contacts 12 of.

through the winding of the primary magnet PM, it is necessary to provideanother circuit for said winding. This is obtained through the contacts53-51 of said magnet,-

the wiper 56 and the gIO-ellldd contact 57. Consequently, the magnet PMremains energized at the time the wipers are in their second position;and through the instrumentality of the magnet SM, the wipers are steppedinto their third position, into engagement with the first set of bankcontacts 66, 67 and 68. If the link-circuit connected to these contactsbe in use, a multiple ofit-he contact 68 will be connected toground,through the wiper 56, contacts 5169 and the winding of the releasemagnet RM of another individual switch. Conse uently, the circuit of theprimary magnet broken and the wipers will be moved an other step. Thisstep-by-step movement will continue until the wiper 56 engages a contact68 of an idle link-circuit. Upon such engagement, the circuitthrough/the primary magnet will-be opened, and its contacts 50 and 51will return to normal, the former interrupting the circuit of thesecondary mag- -net SM and the circuit of the cut-off magnet CO, and thelatter placing ground on the contacts 68 of the link-circuit thusconnected, thus making it busy to other calling lines. It will be notedthat when the cut-off relay CO is energized, its armature contacts 47and 48, by engaging fixedconta-cts 69 and 70, connect the line limbs SPto the connected bank contacts 11 and 12 re- M will remain unspectively.From this it will be seen that the operation of the individual switch C,resulting from the calling partys removal of his receiver from its hook,automatically connects his line to anidle link-circuit, places potentialon the contacts 12 of the connector switches associated with said line,

and grounds the contacts 68 of the selected link-circuit.

The next step in the calling operation consists in moving the dial 71 ofthe calling machanism T until three of the teeth 72 (corresponding tothe thousands digit in the number 31456) pass below the contact spring-73, and then allowing it to return to normal under the tension of thespring 74. Upon its return, contact springs 73 and 75 will be engagedthree times and this will be followed by a single engagement of thecontact springs 76 and 77, since, in the normal position of the disk,one tooth lies below the spring 76. The three engagements of the--springs 73 and 75 send'three impulses of current overthe line limb P,while the single engagement of the springs 7 6 and 77 sends a singleimpulse over the line limb S. At

the time these impulses are being transmitted. the bridge through thetransmitter 41, is interrupted at the contacts 42 which separate whenthe dial 71 is moved fromits norted over the line limb P energize anddenergize the primary relay PR three times, while the following singleimpulse over the line limb S energizes the secondary relay SR once. Thecircuit for the primary relay extends from the live pole of the battery,through the winding of said relay, the normally closed contacts 78 and 79 of the control switch CS, the link-circuit strand 80, individualswitch contacts 6614 relay contacts 48- 1 9, line limb P, contacts 7375to ground at 81. The corresponding circuit forthe secondary relay SRextends from the live pole of the battery 45 through the winding of saidrelay, the normally closed contacts 8283 ot'vthe switch CS, thelink-circuit strand 8 1, individual swtich contacts 6715, line limb S,to ground at 81. Each impulse transmitted through the primary I relay PRtransmits corresponding impulses through the winding of the primarymagnet PM of the first selector'switch E. This circuit may be tracedfrom the live pole of the battery 85, through the winding of magnet PMnormally closed contacts 86-87 of the release magnet RM of saidselector, normally closed contacts 88 and 89 of the oftnormal switch 0associated with the first selector E and contacts 9091 of the primaryrelay PR to, ground.

The selector switch is so constructed that its wipers 92, 93 and 94 aregiven a primary movement in one direction, followed by a secondarymovement at an angle thereto. By the primary movement, the wipers arebrought opposite a level or group of bank contacts connected tocorresponding selector switches and, by its secondary movement, an idles cond selector switch is selected. Thus, in response to the threeimpulses transmitted from the primary relay PR, the primary magnet PM,through the agency of its associated mechanism hereinafter described,causes the wipers 92, 93 and 9.4 to be stepped to the thirdlevel of bankcontacts which are those assigned for connection to the third thousandgroup of subscribers lines. The following impulse transmitted over theline limb S, which energizes the secondary relay SR, closes a momentarycircuit from ground at the contact 91 of said relay, through the contact95, contacts 9697 of the ofi-normal switch 0, the winding of the privaterelay 98 to the live pole of the battery 85, thereby energizing saidrelay to break the normal contacts 99 00, 101-102, 103-104, and to closecontacts 103105 and 106-10 1. By the first primary movement of theselector switch E, the contacts 1 07-108 are menet 98 is energized,current will flow over a circuit including the winding of the secondarymagnet 8M the contacts 110 110 105-103, 109-107 and 110-111 to ground.The magnet SM by reason of its vibratory circuit and its mechanicalconnection with the wipers 92, 93 and 94, steps them over thecooperating bank contacts 112, 113 and 11 1. As soon as the circuit ofthe private relay 98' is interrupted, its contacts are returned to theirnormal positions and consequently the circuitof the secondary-magnet SMisinterrupted and the stepping of the switch ceases. Therefore, whilethe wipers are passing over busy contacts, an energizing circuit for themagnet 98 isma'inta'ined. If any encountered contact 112 is that of abusy link-circuit, it will be connected to ground through one ofitsmultiple contacts, the wiper 92 of another selector switch, and'over acircuit of said switch to ground, as follows: through the normallyengaged contacts 112 -113 of the release magnet RM contacts'104-103 ofthe private relay, contacts 109-107 and contacts 110-111. Therefore, aslong as the Wiper 92 of the selecting switch engages a will be energizedover a circuit from the grounded contact 112, the private relay 98 livepole of the battery 85, through the winding of said relay, contacts106-104, 113-1J2 wiper 92 and contact 112 to ground, As soon, however,as an idle linkcircuit is encountered, this circuit will be lnterruptedand the further progress of the switch stayed, thus completingconnection from the calling station, over the heavily marked circuit tothe contacts 113-114 of the link-circuit connecting with an idle secondselector switchF. In the operation of the selector switch E, it will benoticed that the wipers 93 and 94 were disconnected from a the circuitby the contacts 99-100, 101-102 of the private relay 98 while passingover the contacts 113-114 of busy link-circuits, thus preventinginterference with conversation through contacts in multiple therewith.

The next step in the calling operation consists in again moving the dial71 farenough to bring four teeth (correspondin to the hundreds digit inthe number 3456) below the contact spring 73 and then allow- 1 ing it toreturn to normal, thereby transmitting four impulses over the line limbP to actuate the primary relay PR four times. i

This, as before, willbe followed by a-single impulse over the line limbwhich will impulses will cause the second selector switch F to move itswipers 115, 116 and 117 to the fourth level or group of bank contacts118, 119 and 120, which areassigned for connection to the fourth hundredgroup of subscribers lines and thence into engagement with an idlelink-circuit con- 1 contacts 138-139 and necting with an idle connectorswitch G havmg access to the'called subscribers line.,

lease magnet RM the winding of the primary' magnet PM to the live poleof the battery 85.

The impulses transmitted through the magnet PM are instrumental inproducing the primary movement of the Wipers 115, 116 and 117. The firstmovement from normal will cause the contact 125 to disengage the contact126 and engage the contact 127 and in addition, will cause the contacts.128 and 129 to engage, and the contacts 130 and 131 to engage. Theimpulse transmitted by the secondary relay SR will close a circuit fromground at the contact 91, through contact 95, contacts 101-102, wiper94, contact 114, contacts 132-133 of the off-normal smitch O winding ofthe private relay 133 of the second selector switch F to the live poleof the battery 85, thereby energizing said relay and causing it todisconnect the wipers 116-117 from circuit by separating the contacts134-435 and the contacts 136-137, 'while at the same time breakingclosing contacts 138-140 and contacts 141-139- The energization of theprivate relay 133 thus completes a circuit for the secondary magnetSMQ-by which the wipers 115, 116 and 117 are given their secondarymovement.. This circuit extends from the live pole of the 'bat-..

, tery 85, through the winding of said magnet SM contacts 140 -1 10",140-138, 127-125, 128-129 to ground.

By reason i of the vibratory. character of this circuit,

the secondary magnet SM will step the Wipers around over theirassociated bank contacts until its circuit is interrupted.

This occurs, as previously indicated in connectlon with the descriptionof the'first selector switch E, when an idle link-circuit" isencountered. At this time, as previously indicated, the wipers 116-117are again included in circuit, thus projecting the circuit of thecalling. line through the individual switch 0 of Said line and selectedswitch mechanism D, E, F and G.

The next step in the calling operation con sists in moving the dial 71into "a position 1 "through the primary relay PR, followed by a singleimpulse over'the line limb S through the secondary relay SR. Thepritotransmit five impulses over the line limb actuate the secondary relay SRonce.. These P mary relay over a circuit extending from its.

12s mar'y impulses are extended from the prii 135, 134, wiper 116,contact 119, contacts 142-143 of the off-normal switch 0 of theconnector, contacts 144-145 of the release magnet RM* of said connector,through the winding of the primary magnet PM to the live pole of thebattery 146. In this instance the five impulses of current transmittedthrough the primary magnet, will step the-wipers 147-148 to the fifthlevel of contacts to which subscribers lines, having numbers from 50 to59 inclusive, are connected. At the first movement of the switch inresponse to these primary im-' pulses, the switch contacts 147-147 aremoved into engagement, thereby grounding the associated bank contacts118 through the winding of the release 'magnet RM. The secondary impulsefollowing these primary impulses closes a circuit from ground at thecontact 91 of the secondary relay SR, to the wiper 94 of the firstselector switch E, as previously traced, thence through contact 114,contacts 136-137, wiper 117, contact 120, contacts 149-150 of theoff-normal switch 0 contacts 151-152 of the release magnet RM, windingof the secondary magnet SM to theilive pole of the battery 146. Thiscauses a momentary energization of the secondary magnet SM, which isinstrumental in giving the wipers one step in their secondary direction.

As indicated in Fig. 6, the wipers are normally two steps distant fromthe first set of bank contacts and consequently this single step doesnotbring them into engagement, but is occasioned for the purpose ofactuating the off-normal switch contacts 142-148. At this time, thecontact 142 is movedfrom engagement with the contact 143 into engagementwith the contact 153; and at the same time, the contact 149 is movedoutof engagement with the contact 150. The contact 149 is not moved intoengagement with the contact 154 until the next step of the switch. Thisis to prevent the above secondary impulse from being transmitted throughthe upper winding of the husy relay 160 by way of the contacts 159-158,which might occur if the contact 149 were thrown at once into enga ementwith contact 154.

he next step in the calling operation consists in moving the dial 71 soas to transmit primary impulses, again followed by a single secondaryimpulse. In this case, the circuit under the control of the primaryrelay PR is the same as that heretofore traced, as far as the contact119. Thence it extends through the contacts 142-153 of the 0dnormalswitch 0, contacts 155-156 of the control relay 157, through the windingof the secondary magnet SM to the live pole of the battery." Thus thesecondary magnet is energized and deenergized six times, therebystepping the wipers 147-148 into engagement with the sixth pair ofcontacts which follows the six primary impulses is extended by thesecondary relay SR to the contact 120 of the second; selector switch F,over a path the same as that heretofore traced. From this point, itscircuit is continued through the contacts 149-154 of the off-normalswitch 0 contacts 158-159 of the control relay 157, the upper winding ofthe relay 160, which controls the application of the busy signal, to thelive pole of the battery 146. The completion of this circuit momentarilyenergizes the relay 160 to' close its contacts 161-162 and 163-164, thusmomentarily applying busy current to the line. -In case the desired lineis in use, we have seen that a potential above that of ground will existon the contacts 12 connected therewith. Consequently, if the called lineis busy, at this time, a path for current will be completed from theengaged contact 12, through the wiper 148, switch contacts 165-166,contacts 167-168 of the release magnet RM, contacts 161-162 of the busyrelay 160, through the lower winding of said relay to ground. Thewindings on this relay are so arranged at this time that their effectwill be cumulative and consequently the contacts of the relay will belocked in their alternate position,

thus applying said busy signal to the line. This may be accomplished inany preferred manner, but in the resent instance is obtained by means ofan interrupter I included in a primary circuit with one winding of aninduction'coil 169 and with the battery 146. The secondary circuitextends fromground at the battery 146, through said battery, thesecondary windingof the induction coil 169, the condenser 170, relaycontacts 163-164, off-normal switch contacts 154-149, second selectorswitch contacts 120-117, relay contacts 137-136, first selector switchcontacts 11494, relay contacts 102, 101, condenser 171, individualswitch contacts 67-15, relay contacts 46-47, line limb S, contacts 42 ofthe calling device T, transmitter 41, switch-hook 40, line limb P, relaycontacts 48-49. individual switch contacts 1466', control switchcontacts 79-78, winding of the rimary relay PR, battery 45 to ground. hecurrent induced in this secondary circuit will produce the customaryclick in the receiver of the calling party, as an indication to him thatthe called line is busy. In case the called line is not busy, the finalsec: ondary impulse transmitted from the calling station will onlymomentarily energize the busy relay 160 and will therefore, at the most,apply only a momentary busy signal which may be disregarded by thecalling party. Upon the deenergization of this relay, its mechanicalconstruction is such, as will be hereinafter more fully explained, as tocause a movement of the contact 165 from engagement with the contact 166and into engagement with the contact 172, thereby completing a circuitfrom the live pole of the battery 146, through the winding of thecontrol relay 157 contacts 172-165, wiper 148, contact 12, contacts61-62 of the oilnormal switch 0 associated with the called line, throughthe winding of the cut-ofii relay CO to ground, thereby actuatin bothrelays. The actuation of the cut-o relay completes the connection of theline limbs S-P, through the contacts 48-69 and 47-70 to the connectorswitch contacts 11 20 and 12, while at the same time disconnecting saidline limbs from the movable contacts or wipers 14-15 of its individualswitch. By means of this circuit, a potential above that of groundexists at the multiple contacts 12 as well as the test contacts 0 thejacks 10, thereby rendering the line busy to either manual or automaticconnection. The energization of the relay 157 in terrupts the circuit ofthe secondary magnet SM at the contacts 155-156 and completes thestrands of the talking circuit at this point atthecontacts 155-173 and158-174. At the same time, the grounded contact'17 5 is brought-intoengagement with the contact 176 which completes a circuit through thenormally closed contacts 177-178,the'wind-- ing of the ringing relay179, to the live pole of the battery lfifig ltheije'by actuatin the relay 179 and ""nipl'eting circuit rom the live pole of battery fl4 l6,through the resistance 1 contacts-i1581-182, wiper 148,

ing 0 the ringing' r'elay 179, wiper 147, contact 11, contacts 69-48,line limb P, switch-hook 4.0, call-bell 186, condenser 187, line limb S,

contacts 47-70, and thence to ground by way of contacts 12-148,181-182,resistance 180, battery 146, or by way of the ofi-normal switch contacts61-62 and the winding of the cut ofi' relay CO, thereb actuating thecall-bell as a signal to the ca led party. By means of the interrupterI, ringing current is intermittently transmitted from the gene eratorG;'and durin the non-transmitting intervals, the circuit is grounded at188.

, The relay 183 is so constructed that the passage of'the ringingcurrent from the genorator through its winding will not move off-normal"switch contacts its contacts from normal position. In addi-'.

-tacts 191-90 of the primary relay PR, contacts 99-100 of the privaterelay 98, first selector switch contacts 93-113, relay contacts 135-134,secondary switch contacts 116-119, off normal switch contacts 142-153,relay contacts 155-192, release magnet contacts 193-194, contacts195-196 of the release relay RR, to ground. The completion of thiscircuit energizes the control magnet CM which is constructed so as toactuate the switch contacts of the control switch CS upon itsdenergization. As' soon as the called party removes his receiver fromits hook, therebycompleting a conductive bridge between the line limbs Sand P through histransmitter, a circuit is completed from the live poleof the battery, through resistance 180, contacts 182-181, wiper 148,contact 12, relay contacts 7 0-47 line limb S. through the substation,line limb P, relay contacts 48-69, contact 11,

wiper'147, contacts 184-185, through the lower winding of relay 183 andthe interrupter I to ground. The flow of current over this circuit issufficient to cause the relay 183 to move its contacts to theiralternate position, thereby completing the adjacent portions of thelink-circuit strands at the contacts 197-198 and 199-200, interruptingthe circuit through the" ringing relay at the contacts 177-178 andbringing contacts 178 and 201 into engagement. The breaking of theringing relay circuit discontinues. the application of ringing currentto the called line, while theengagement of the contacts 178-201completes a circuit from the live pole of thebattery 146, tlfrough theupper winding'of the relay 183, contacts 201-178, 176-175, to ground,thereby maintaining the contacts of the relay 183 in their actuatedpositions. As soon as the relay 183 is actuated, transmission currentfor thecalled line is supplied over a-circuit extending from the livepole of the battery 146, through the winding of the control relay 157,switch contacts 172-165, wiper 148,

contact 12, out over the line limb P throughf their alternate position,thereby again interrnpting the circuit of the magnet CM at the contacts189 190, connecting the ad a'cent pdrtfi'nrof the link-circuit strandsat contacts T9-202 and 83-203, and interrupting the normal circuitthrough the primary and secondary relays PR and SR. Transmission currentis furnished to the calling line from the battery 15 over a path leadingfrom its 10 live pole, through the upper windings of the relays QQi and205, control switch contacts 202-79, individual switch contacts 66-44,line limb P, through the transmitter 41 at the substation, line limb S,wiper 15, contact 67, control switch contacts 83-203, and the lowerwindings of the relays 205 and 204 to ground. The windings on the relay205 are serially arranged so that, upon the movement of the controlswitch contacts to their alternate positions, said relay is energized toclose its contacts and thereby close the final break in f ieitalkingcircuit between the connectedstations. By this means, the talking Vcircuit remains open until the called party responds. This is of valuewhere the substations are equipped with pay station devices. Thewindings of the relay 204 are wound in opposition so that, upon theclosure of the circuit just traced, its contacts are not disturbed. Bymeans of the condensers 206-207 in the strands of the link-circuitassociated with the connector G, the .ends of said circuit areconductively separated, but permitting the passage of voice currents. Atalking circuit is thus established between the calling and the calledstations, as indicated-by the heavy lines of the diagram. ii

. In order to restore the parts to normal q/osition at the end ofconversation, it is only necessary foneither or both parties tohang uptheir receivers. Associated with each siwgitch-hoglgjl? are contactsprings 208, 209.:an'd 211), 208'and'209 being connected re- ?5spectively to the line limbs S and P, and 210 beinggro11nderl,,)Vl1enthe receiver is renroved from the switch-hook, a projection 211 passesover the upper end of the spring .208 without causing an engagement ofcontacts; but upon the return of the receiver to the switch-hook, thesprings 208, 209 and 210 are forged into engagement, thereby groundingbotlrgline limbs at the substation.

It will be remembered that the circuit for supplyingtransmission-current to the calling statiom extends from the live poleof the battery 45 .Wthrough the upper windings of relays 204 and 205,thence over the heavily markedcircuit, through the substation, and 6back through the lower windings of the relays 205 and, '201 toj 'ground.Therefore, when the c: illing-subscrib er restores his receive? to theswitch-hook and thereby grounds both line lii nbs, the normal balance ofthe r'elay204 is destroyed, and the release magnet RM is energized overa circuit extending from the live pole of the battery 45, through thewinding of said magnet and the contacts of the relay 204 to ground. Onthe other hand, it will be remembered that the circuit for supplyingtransmission current to the called line extends from the livev poleofthe battery 146, through the winding of the relay 157, switch contacts172-465, out over the line, through the substation, and back through thewinding of the release relay RR to ground. Therefore, the restoration ofthe called partys receiver to its hook interrupts the circuit andthereby closes the contacts 195-496 of the relay RR and thus completes acircuit from ground at said contacts, through contacts 194193 of therelease magnet RM, ,contacts l92-155 of the control magnet 157, over oneside of the heavily marked circuit, to the upper contact of the relay205, thence through the upper winding of said relay and the relay 204 tothe livepole of the battery 45, thus providin an unbalancing circuit forthe relay 204 rom the called station to cause the energization of therelease magnet RM. The energization of the release magnet RM closes acircuit from the live pole of the battery 85, through the Winding ofthe.release magnet RM the contacts of the release magnet RM, contact 68,wiper 56, contacts 51-69 of the primary magnet of the individual switch0, and the winding of the release magnet RM of said switch to ground.The energization of the release magnet RM in turn completes a circuitfrom the live pole of the battery 85, through the protective resistance212, contacts 213112 of the magnet RM wiper 92, contact 112, contacts130131, winding of the release magnet RM to ground. The energization ofthis latter magnet in turn completes a circuit from the live pole of thebattery 85, through the protective resistance 214, contacts 215-216 ofthe magnet RM, wiper 115, contacts 118, 147 447", and the winding of therelease magnet RM of the connector switch G to ground. From this, itwill be seen that it is necessary-to maintain the unbalancing circuit ofthe magnet 204 from the calling station until the release magnets RM,RM, RM, RM, and RM have attracted their armatures. The energization ofthe release magnet RM of the lndividual switch C closes the contacts w-b0l in bridge of the contacts of the cut-0d relay CO; and, as will morefully appear hereinafter, returns the oif-normal switch contacts 58, 59and 60 to their normal positions, thereby completing a circuit from thelive pole of the battery 45, through the resistance 65, contacts 59 -5s,a e-c2 and' the winding of the cut-ofl' relay CO to ground. The cut-oilrelay CO is thus energized to break the circuit through its contacts4=647,

V cuit from the calling station for the magnet 'RM is deenergized'."Upon thedeenergiza- As soon asrthe wipers energizing the'private magnet98 pole of the' the winding of said- 48-49, and the closed contacts ofthe release magnet RM maintain the unbalanoing cir- 20&. As soon asground is removed at the calling station, the contaetsof the relay 20 1are restored to normal and each of the release magnets RM, RM, RM RM andtion of the release magnet RM, the wipers 14, 15 and 56 return to theirnormal positions. In so doing, they pass over the multiple contacts ofother link-circuits and, by reason of the disconnection of the wipersfrom the line, interference with conversation over any of theselink-circuits is prevented.

reach their normal positions, the contacts 61-62, 63- 64, of theoff-normal switch are returned to their normal positions and the circuitof the cut-off relay CO is thereby interrupted, and the normalconnection of the line with its wipers again established. At the firstselector switch E, the energizationof the release magnet RM moves theswitch contacts 107, 108 and 109 to their normal positions, thus over acircuit extending from the live battery 85, through magnet, contacts108-r107 ground. 1

The energization-of the private magnet disconnects the wipers of theswitch from and 110-111 to the line so as to prevent interference withconversation over multiply connected linkcircuits, as previouslyindicated. At the same time, the energization of the release magnet, byclosing itscontacts f -g, bridges the opening at the contacts 99-100 andthereby maintains the unbalancing circuit from the called stationthrough this switch. In a similar manner, the wipers 116 -117 of thesecond selector switch F are disconnected and the unbalancingcircuit ismaintained 1 by the closure of the contacts lap-. Upon thetdeenergization of the release magnet RM, the contacts of the controlsw1tch CS are returned to normal position. Likewise,

upon the deenergization of therelease magnets RM RM of the selectorswitches, Where the balance of the magnet 204 is destroyed 'by thereturn of the called subscribers receiver to its hook, the unbalancmgcircuit is interrupted at the contacts 193-494 of the release magnet RMas soon as the energizing circuit is completed therethrough by theactionof the release magnet RM of the sec-, ond selector switch. Thedeenergization of.

the release magnet RM restores the connector to its normal position. Aspreviously pointed out, during connection there'is a c1r.-

through the winding of the control magnet 157, switch contacts 17 2-165,wiper 1418, contact 12, contacts 6162 and the winding current willflowfrom cuit from the live pole of the battery 146,

of the cut-ofi' relay to ground. As soon as the wiper 14:8 leaves thecontact 12 upon the return of the switch, this circuit is interruptedand the cut-oifrelay contacts are allowed to return to normal toestablish con' nection between the called line and the wipers 14.-15 ofits individual switch C. The contacts of the control magnet 157 alsoreturn to normal and thereby interrupt the circuit through the upperwinding of the relay 183, thereby deenergizing said relay. Theenergization of the release magnet RM also restores the'switch contacts165, 166 and 172 to normal. In case the above releasing operation takesplace in response to a busy signal transmitted to the calling line, thenthe 'energization of the release magnet RM interrupts the lockingcircuit of the busy relay 160 at the contacts 167-168, therebyinterrupting the secondary circuit of the induction coil 169. If thecalling party desires to restore the mechanism at the exchange to normalat any time priorto the completion of connection with the called line,the restoration of his receiver will simultaneously energize the primaryrelay circuits which have been traced heretofore.

PR and the secondary relay SR over As previously indicated, thesecircuits remain intact until the called party responds to the call. Uponthe simultaneous energization of both relays PR and SR, their con- 5tacts 7c-Z will be moved into engagement thev individual switch will berestored to normal in the manner previously indicatedand, as before, therelease of the switch E will occasion the release of the second selec-.

' tor "F and the connector G, should they be in circuit at the time.

With reference to establishing connection between a manually equippedcalling line and an automatically equipped called line, it will beobserved that the cut-off relay CO of the automat cally equipped line isincluded in circuit between the sleeve contact of the jacks 10 andground, while the line limbs are normally disconnected from the jackvcontacts-the same as in the manually equipped line illustrated.Therefore, upon inserting the calling plug 32'into a jack 10 associated,for example, with the line S-P,

the sleeve contact of the jack, through thenormally closed contacts 6162of the ofi-norma-l switch 0 and the winding of the cut-off relay CO toground, thereby extending the line limbs to the bridge through thetransmitter and closes that through the call-bell in the same manner asat the manually equipped substation. Similarly, upon establishingconnection between an automatically equipped calling line and a manuallyequipped called line, the engagement of the wiper 1480f the connectorwith one of the contacts 12, associated withsaid called line, willcomplete a circuit through the control magnet 157 and the cut-off relay29 in a manner similar to that described in connection with anautomatic'ally equipped called line. Thus the cut-off relay 29 will beactuated and a called line circuit, substantially the same as that ofthe automatically equipped line, will be established. At the end ofconversation, the restoration of the receiver to its hook by the calledparty will have the same effect upon the interconnecting apparatus asthat described in connection with an automatically equipped called line.Obviously, in the practice of the system above outlined, any preferredmechanical construction may be employed for performing the switchingfunctions -indicated. However, I preferably employ the switch mechanismillustrated in the drawings.

Referring first to the individual switch C, the fixed contacts 57, 43,44, 66, 67, 68 are arranged in abank 217, mounted upon a suitablesupport such as the metal plate 218, carried upon any suitable framework219. The contactsin the bank are insulated from each other in anysuitable manner, such as indicated in Fig. 8, and the contacting endsarearranged in an arc in a position to. be

engaged by the wipers 14, 15 and 56, which are suitably mountedupon, andinsulatedfrom, a supporting shaft 220, normally held the positionindicated by the spiral retractile spring 221, contained in a casing 222and havng one endsecured to the fixed support 223. As' illustrated, thewiper 56 is made double and is adapted to straddle the middle row ofcontacts 68, while the outer wipers 14 and15 engage the contacts 66 and67 respectively. The fixed contacts 43 and 44, as clearly illustrated,engage the wipers 14 and 15 in the first and second.

-positions in the manner previously described. All the wipers andcontacts are provided with suitable terminals for the connection ofcircuit wires. The portion of are adapted to be engaged by the retainingpawl 226 to hold the shaft in its various operating positions. Anactuating pawl 227' cooperates with the ratchet member to rotate theshaft step by step. The ratchet member 225 is also provided with aprojection 228 which normally holds the springs 61, 62, 63 and 64 of theoff-normal switch 0 in the position illustrated. When this projection ismoved from its normal engagementwith the stop'229, the contact springsare moved to their alternate positions by reason of their'inherentspring tension, The remaining springs 58, 59 and" 60 are held in theposition'illustrate'd by the spring member 230 which is carried by thearmature 231 of the release magnet RM carried upon the plate 218. Theupper end of the retaining pawl 226 is adapted to pass through anopening in the spring member 230. This opening is so placed that whenthe relay RM is energized the member 230 soon as the end of the paw-lpasses into the opening ,in the member 230, the latter engages thecontact spring 58 to restore it to its normal position. This movement ofthe switch contacts, it should be noted, is done upon theattraction ofthe armature 231 and not upon its retraction. In order to free -theretaining pawl 226 from the member 230, said member is provided with aninclined projection,232 which is adapted to be engaged by a frictionrollercarried at the end of an arm 233, forming an extension of thearmature 234 of the secondary mag-' net SM. This armature also carriesthe actuating pawl 227.. Upon the first attractionof the armature 234,the spring mem-, her 230 is moved upward out of engagement with ,the end.ofthe retaining pawl 226, and the latter is allowed to move intooperative position. under the tension of its spring. The plate218-carries the contacts 54 and 55 which are causedto interrupt thecircuit of the secondary magnet SM. This "plate also carries the primarymagnet PM and the cut-off relay CO with their associated contacts, aswellnas the associated contacts of the release magnet RM. From the aboveit will beseen, that the first impulse transmitted through :thesecondary magnet SM will place t e :retaining pawl 226 into operativeposition: and begin the I so step-by-s tep movement of the wipers; thatupon theyenergization of the release magnet RM, the spring 58 will bereturned to its normal position;" the retaining pawl 226 will be engagedby the member 230preparatory to its removal from operative position; andthat upon the de'e'nergization of said magnet, such removal will takeplace.

Referring now to the connector switch G,

which is illustrated in Figs. 5 to 10inclusive, 235 designates asuitable supporting frame for the switch mechanism, which includes theprimary magnet PM, secondary magnet SM", the release magnet RM, themagnet 160 for controlling the busy "signal, and, if desired, anadditional magnet such as the ringing relay magnet 179. The frame alsocarries the fixed contacts 11-12-which are arranged in a bank 236 withtheir free ends adapted for the attachment of connecting wires andhaving their contacting inner ends terminatingin a spherical surface.These contacts are suitably insulated from each other in themanneiuillustr'ated in Fig. 8, by the insulating strips 237 supported ona frame 238. At the center of the spherical surface formed by the innerends of the bank cont'acts, the wipers 147 and 148 are pivoted tothelower end of a rotary shaft 239. carried by the frame 235. The wipersare rotatable with the shaft in a horizontal direction and, in addition,may be rotated vertically about their pivot 240 through the agency of anadditional longitudinally movable shaft 241 having a. broad foot 242which engages a rearward projection 243 on the wipers. Thus by rotatingthe shaft 239, the

wipers may be given their primary movement to the desired level or groupof bank contacts and, by subsequently giving the shaft 241 alongitudinal movement, the wipers may be moved to the desired bankcontact in the selected level. The foot 242 on the shaft 241 is madesufliciently large to engage the projection 243, no matter what theposition of. the wipers may be. The

v mechanism associated with the primary magnet PM, for giving the shaft239 its prnnary or rotary movement, comprises an actuating pawl 244carried by the armature and adapted to engage the teeth of the ratchetwheel 246 to ,step the shaft around.

The shaft is retained in its various positions by the retaining pawl 247whi'ch is adapted to engage the teeth 'of the ratchet wheel. The

- upper end .of the shaft 239 carries a member 248 having maintains thecontacts 147 and 147 out of a projection 249 which normally engagement;but upon the first movement of the shaft, allows them to contact. Thesec-r ondary magnet SM, through the agency of "its armature 250,actuating pawl 251 and the ratchet teeth 252 on the shaft 241, steps thelatter downward to carry the "contacting ends of the wipers into theirdesired posiwhich, after the first movement of the shaft,

. engage the ill.

tions. A suitable retaining pawl 253v engages the teeth 254'on the shaft241 to hold it in its different operating positions. The shaft is alsoprovided with a" spline 255 engages the teeth of the ratchet wheel 246to lock the shaft 239against rotation. The contact'springs 142, 143 149,150, 153 and 154 are normally held against their spring tension in theposition illustrated in Fig. 1, through the agency ofa projection 256carried at the upper end of the shaft 241. The outer end of thisprojection normally engages a pin 257 to hold the spring contacts inthis position. The-spring 142, which normally engages the springcontact153, moves into engagement with the spring contact 143 upon the firststep of the shaft 241; while the spring 149, which is normally inengagement witht'he spring 150, does not engage the spring 154until theshaft 241 has been moved two steps. This is brought about by properlyspacing the springs, as illustrated in Figs. 6 and 9. The armature 258of the magnet 160, also carried by the frame 235 when attracted, bringsthe contact springs 161- 162, 163-464, into engagement. Sim1- larly',the armature 259' of the release magin Fig. 10 and, as previouslypointed out,

the contact 165166 is broken and the contact 165.172'.made upon theretractionof the armature 258, while the parts are restored to normalupon the energization of the release magnet RM This is brought aboutthrough the agency of an arm 260 carried at the free end of.the armature258 and having its outer end forced upward by a-spring 261.- Upon theattraction of the armature 258, a projection 262 on the arm,11 260passes to the left of a block 263 carried by the spring 165; and uponthe retraction of the armature 258,,the right hand shoulder on theprojection 262, by engaging the left face of the block 263, forces thespring 165 to its alternate position. In order to release of the arm 260so that, upon the attraction of the armature, the outer end of the arm264 is drawn downward so as to free the projection 262 from the block263, to allow the return of the spring 165 to its normal position. v

In order to restore the wipers to normal after they have been once movedto an operative position, it is only necessary to disretaining pawls 247and 253,.

whereupon, through the agency of a spiral spring 265, located about thepivot 240, the shaft 241 will be restored to normal; and. through theagency of a. spiral spring 266 contained in a casing 267, the shaft 239and wipers will be restored to normal. As illus tratedin Figs. 5 and 9,the retaining pawl 253 is pivoted in a bracket 268 carried by the frame235, and is forced into engagement with the shaft 241 by the spring 269.Thetail 270 of this pawl normally rests against the under side of adownwardly-de pressed member 271, pivotally secured to the lower endofthe armature 259 at the release magnet RM and movable therewith.

Similarly, the tail 272 of the retaining pawl 247 rests against theunder side of this member 271. Said member is provided with openings273and 274 which are adapted to slip over the tails of the pawls 253 and247 respectively when the armature 259 reaches its attracted position.From this, it will be seen that when the release magnet RM ,isdeenergized and its armature 259 retracted, the member 271 will remainin engagement with the awls and draw them out of o erative posltion. Thepawls and the mem er 271 remain in this engaging reflation while theconnector switch is not in use. At the beginning of the operation of theswitch, however, and at the first impulse transmitted through theprimary magnet PM, the engagement whednember 271 with the pawlsnsbr'okemand they are allowed to return to their active positions. This latter isaccomplished throu h the agency of a lever 275 pivoted at 2 6 and havingone end pressed by a s ring 277 into engagement with the end 0 theprimary magnet armature 245.- The opposite end of the lever 275 isprovided with .an upturned end 278, having a friction roller 279 whichnormally rests against the under side of the member 271 and which, uponthe first movement of the armature 245, is rocked against the inclinedface" 280 on the under side of the member 271 to force said memberupward out of engagement with the retaining pawls.

'The selector switches E and F partake of the general character of theconnector switch G, ust described. Figso13 and 14 illus-' trate aselector switch with the contact arrangement of the second selectorswitch F. In this instance, there are three wipers which coiiperate withthree'sets of bank contacts in the same manner as the wipers andcontacts of the individual switch C. The contacts in this case, however,are arranged in spherical formation as in the connector switch, and thewiper. are given their movement through the agency of primary andsecondary magnets in the same manner, ex cept that the secondarymagnet1s provided with a vibratory circuit. The mechanical arrangement foraccomplishlng the movemagnet RM Upon the first rotary or primarymovement" of the selector, the contact springs 128, 129, 130 and 131 areallowed'to move from their normal positions, illustrated in Fig. 1, totheir alternate position, in the same manner as the springs 147 and 147b of the connector are allowed to engage. Similarly too, upon the firstdownward movement of the shaft 241, by which the wipers are given theirfirst secondary step, the contacts 121122, 132133 are moved to theiralternate positions. In the selector also, the releas'e magnet RMis-pro'vided with a pawl engaging member 271, which, upon thedeenergization of the release magnet, draws the pawl out of operativeposition. In this instance, the pawls are released from engagement withthe member 271 by a lever mechanism similar to that described inconnection with the connector switch upon the first actuation of r theprimary relay. In the present instance, the upturned end 278 of thelever 275 does not engage the member 271 directly, but through anintermediate lever 281.

This

member is normally pressed by a spring 282 sition is the normal positionof the springs.

Upon the first energization ofthe primary magnet by which the primaryand secondary retaining pawls are released, the catch 283 alsodisengages the spring 125 and allows it to move to its alternateposition. It remains in this position until the switch is restored tonormal by the operation of the release For this purpose, an arm 284,carried by the armature of the nzagnet and extending at its outer endinto a position to engage the far side of the spring 125,

is provided. Upon the energization of the release magnet, this arm drawsthe spring 125 into engagement with the spring 126 and it is retainedthere by the catch 283. The first selector switch E is substantially thesame as the second selector switch F, but as indicated in the diagram,is provided with fewer'contact springs operated upon its first primarymovement.

.The mechanism by which the actuating magnet CM and the release magnetRM operate upon the contacts of the control switch CS, is illustrated inFigs. 11 and 12. As previously pointed out, the contacts of this switchare moved to their alternate positions upon the denergization of themagnet .CM, and are restored to them normal positions upon thedenergization of there- The spring arrange lease magnet RM. ment of thisswitch is illustrated in Fig. 12, wherein the insulating spacers 285 and286,

carried at the upper end of the lever 287 of the magent CM, are adaptedto move the 1 contacts to their alternate positions. The armature 288 ofthis magnet carries a spring pressed arm 289 which is provided with acatch 290 at its outer end,'adapted to engage the lower end of the lever287.

Normally, the catch 290 is in non-engaging position. Upon the attractionof the armature 288, the arm 289 is moved far enough to allow the catch290 to engage the lever 28'} and upon the-retraction of the armature,the lever is. rocked about its pivotal support, so as to force thespacers 285. and

286-and thereby move the springs to their alternate positions.Cooperating with the arm 2891s, a spring-pressed member 291,.

carriedby theairmature 292 of the release magnet RM. With the springcontacts in their alternate positions, the end of the arm 289, adjacentto the armature 288, will engage the side of the member 291. With theparts in this position, upon the attraction of the armature 292,;of therelease magnet, the member 291,-jwill be drawn downward past the end ofthejarm 289, so, as to engage the under side of its project-z ing end,-Then upon the retraction of the armature 292,the member 291 will-rockthe' arm 289 about its pivot-293 and thereby re-' lease the lever 287,which, on account of the peculiar shape and" the resiliency of thesprings 79, 83 and 190, will return to its normal position, togetherwith the contact springs of the switch." 7

Qbviously, in.=c arrying out my invention, many alterationsandmodifications maybe made in thecircuit arrangements and in themechanical construction of the, switches and relays without departingfrom the spirit and scopeofmyl invention. Obviously too,

the various interconnecting, switches may be locatedifat' adjacent ordistant points. With. 1th 1s-' in view, I have" used the term exchangein accompanying claims in its broad ,senseij' I, therefore, donot wish vto be limited to'jthespecific matter;- disclosed herein,-but aim gtocover by the terms of the 5 appended claims modifications which LettersPatent of the United States. is

legitm'ately J-come1.-i v-ithin thescope of the invention- 7 What Iclaim as new anddesire-to secure 1i A COIIl blIIQCI manual and automatictelephone system, comprising a plurality of telephone lines, ,..part'prov ded only with manuah and par t only with automatic substatlon;-'equipment, manually operated linE-circ uitfiapparatus forestablishing con nection for conversational purposes between a manuallyequipped calling line and any'otherf, desired line and electricallyactuated link circuit apparatus for automatically establishingconnection for conversa-, I

tional purposes between an a utomatically equipped calling .line andanyother desired me. r

2. A combined manual and automatic telephone system comprising aplurality of telephone lines, part" provided only with manual and partwith automatic substation equipment, exchange talking and operatingbattery supply for said system, manually operated" link-circuitapparatus for estab lishing connection for conversational pur-' posesbetween: a manually equipped calling line and any other; desired line,means for .indicating to.the operator the busy .condi-v tion of anycalled line sought to be manually conected Ito, and automatic switchmechanism associated with the; lines having said automatic substationequipment a and controlled by said "equipment to extend the circuits ofsaid lines.

3. A combined manual and automatic telephone system comprising aplurality of telephone lines,-partprovided with manual and part withautomatic substation equip ment, automatically operated link-circuitapparatus under ,the control of said automatic substation equipment forestablishing .connection for conversational purposes between anautomatically equipped calling line and any other desired line, andmeans for automatically indicating to the calling subscriber the busycondition of any "called line sought to be automaticallyconnected.

4. A combined manual and automatic telephone system comprising aplurality of telephone lines, part provided with manual and part withautomatic substation equipment. multiple spring jacks and multi leswitch contacts for each of said lines, llnk circuits andconnecting'plugs for manually establishing connection for conversationalpurposes between different lines, means for" J part with automaticsubstation equipment,

multiply connected spring jacks and mulsaid lines, link-circuits,and'connecting plugs for 'manuallyffpstablishing connection for 'tiplyconnected switcltcontacts for each of a

